There are a number of processes for converting lignocellulosic biomass into liquid streams of various sugars. Certain preferred processes are based on supercritical water (SCW) or hot compressed water (HCW) technology, which offer several advantages including high throughputs, use of mixed feedstocks, separation of sugars, and avoidance of concentrated acids, microbial cultures, and enzymes. Processes using hot compressed water may have two distinct operations: pre-treatment and cellulose hydrolysis. The pre-treatment process hydrolyzes the hemicellulose component of the lignocellulosic biomass and cellulose hydrolysis (CH) process, as its name infers, hydrolyzes the cellulose fibers. The resultant five carbon (C5) and six carbon (C6) sugar streams are recovered separately. The remaining solids, which consist mostly of lignin, are preferably recovered, such as through filtration, and may be used as a fuel to provide thermal energy to the process itself or for other processes.
The CH process uses a significant amount of supercritical water (T>373° C., P>3,206 psi). Generally, the SCW must be generated in a heater at high pressure and pumped into the process. Ideally, lignin of suitable quantity and quality could be recovered during the process to provide sufficient heating value to power the generation of SCW without the need for outside sources of energy. The methods, devices, and systems of the present invention are directed toward these, as well as other, important ends.